Portable Document Format (PDF) is a standard found in common use for electronic documents. PDF is used to represent electronic documents in a way that is independent of application software, hardware, and operating systems. Each PDF file encapsulates a description of a fixed layout, flat document, including the text, fonts, graphics, and other information used to display it. Some PDF files include a field capability that, when used in a PDF, facilitates the creation of forms that may be filled out by the user. The completed PDF form may be saved electronically or printed. PDF-based forms are popular because they support autonomous and disconnected operation.